High-rise architectural structures are often particularly difficult to maintain when it comes to, for example, the inspection, cleaning, and re-application of paint, to their exterior walls and so on, though, which is not necessarily a problem inherent in high-rise architectural structures.
For architectural structures other than high rises, scaffolds such as Beatty frame scaffolds are erected along the exterior walls of the architectural structure with the scaffolding secured (if necessary) to an exterior wall of the architectural structure. A worker stands on it to perform maintenance operations. However, this approach cannot be used for taller architectural structures because the effort to assemble the scaffolding becomes excessive.
For these reasons, the maintenance of a high-rise architectural structure is usually performed by a worker in a gondola suspended from its topmost part. For example, maintenance of a building might be performed by a worker in a gondola suspended from winches installed on the rooftop of that building.
Although it is common to provide maintenance of an architectural structure by a worker in a gondola, as described above, some challenges remain: the number of places from which a gondola can be suspended is limited and the operations performed by a worker in a gondola tends to cause vibration, which can weaken his foothold and increase the level of danger.
Recently, mast climbers, which are also referred to as lift climbers, have been used in some sites for maintenance of architectural structures. They include one or more tall masts and a climbing work platform that can travel up and down along the mast(s). This allows a worker on the platform to perform operations including maintenance operations. Unlike Beatty frame scaffolds, which should normally be set up along the entire exterior wall of the architectural structure, mast climbers involve lower costs and less effort because they can be ready for use simply by erecting the required number of mast(s) to support the climbing work platform and attaching it to the mast(s). Foothold stability is better on the climbing work platform of such a mast climber than in a gondola suspended in the air; thus, from the safety standpoint, it is easier to guarantee the safety of a worker who performs maintenance operations for an architectural structure as compared to cases where a gondola is used.